.jpg) Orbital diagram of2019 AQ3, as viewed from the ecliptic pole | |
| Discovery[1][2] | |
|---|---|
| Discovered by | Zwicky Transient Facility |
| Discovery site | Palomar Obs. |
| Discovery date | 4 January 2019 (first observed only) |
| Designations | |
| 2019 AQ3 | |
| NEO · Atira[1][3] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2460200.5) | |
| Uncertainty parameter 1[1] | |
| Observation arc | 8.20yr (2,296 d) |
| Aphelion | 0.7737AU |
| Perihelion | 0.4037 AU |
| 0.5887 AU | |
| Eccentricity | 0.3143 |
| 164.97 days | |
| 10.152° | |
| 2° 10m 55.92s / day | |
| Inclination | 47.220° |
| 64.4807° | |
| 163.157° | |
| Earth MOID | 0.2267 AU (88.22 LD) |
| Mercury MOID | 0.0549 AU |
| Venus MOID | 0.0384 AU |
| Physical characteristics | |
| 1+km(est.)[1] 0.9–2.0 km(at0.05–0.25)[4] 1.4 km(est. at0.08)[5] | |
| 17.4[1][3] | |
2019 AQ3 is an inclinednear-Earth object of the smallAtira group from the innermost region of theSolar System, estimated to measure 1.4 kilometers (0.9 miles) in diameter. Among the hundreds of thousands knownasteroids,2019 AQ3's orbit was thought to have likely the smallestsemi-major axis (0.589 AU) andaphelion (0.77 AU), that is, the orbit's average distance and farthest point from the Sun, respectively.[6] The object was first observed on 4 January 2019, by astronomers at Palomar'sZwicky Transient Facility in California, with recovered images dating back to 2015.[1][2]
The record for smallest semi-major axis was beaten by another asteroid,2019 LF6, with 0.555 AU.[7]
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2019 AQ3 orbits the Sun at a distance of 0.40–0.77 AU once every 5 months (165 days;semi-major axis of 0.589 AU). Its orbit has aneccentricity of 0.31 and aninclination of 47° with respect to theecliptic.[3] The body'sobservation arc begins with aprecovery taken byPan-STARRS atHaleakala Observatory in October 2015, more than 3 years prior to its official first observation at theZwicky Transient Facility on 4 January 2019.[1] It has aminimum orbit intersection distance with Earth of 0.22 AU or 88lunar distances.[3]
2019 AQ3's orbit has the third-smallestaphelion of any known asteroid in the Solar System, never distancing itself more than 0.774 AU from the Sun (77% of Earth's average orbital distance).[6] Before its discovery, the record was held by(418265) 2008 EA32 at an aphelion of 0.804 AU, which is notably larger.2019 AQ3's orbit also has a semi-major axis below that ofVenus (0.723 AU) and an orbital period of 165 days, which is the third shortest among all asteroids.[8]
2019 AQ3 is a member of the small class ofAtira asteroids,[3] which are also known as Apoheles or interior-Earth objects, as their orbits are confined inside that of Earth's. This makes their discovery difficult, as they stay relatively close to the Sun when observed from Earth, never reaching aSolar elongation of more than 90°, often much less. Only 19 such asteroids are known, 14 of which still reach 90% Earth's distance from the Sun over the course of their orbit.[9]
The asteroid's orbit is also highly inclined with respect to the plane of the Solar System, at more than 47°, the highest inclination of any known Atira asteroid,[9] although there are many near-Earth asteroids with even higher inclinations.[10]
| LINEAR NEAT Spacewatch LONEOS CSS | Pan-STARRS NEOWISE ATLAS Other-US Others |
On the short-term,2019 AQ3 has a fairlyquickly-changing orbit. Between 1600 AD and 2500 AD its aphelion distance lowers slightly from 0.7746 to 0.7725 AU, its perihelion distance increases slightly from 0.4025 to 0.4046 AU, and its inclination increases slightly from 47.19 to 47.25°. It is not subjected to aKozai resonance because although its eccentricity and inclination oscillate in synchrony (when the eccentricity reaches its maximum value, the inclination is at its lowest and vice versa) over a long period of time, the value of the argument of perihelion circulates; the Earth–Moon system and Jupiter are its dominant perturbers.[12]
As of July 2025[update], thisminor planet has neither beennumbered nornamed by theMinor Planet Center.[1]
The object's diameter is estimated at 0.9–2 kilometers (0.56–1.2 miles), which corresponds to angeometric albedo range of 0.05 to 0.25 for anabsolute magnitude of 17.376.[4][5] The Minor Planet Center also considers2019 AQ3 to be larger than 1 kilometer.[1] However, these are estimates with no published radar or infrared measurements providing a more precise value for the body's diameter. As of April 2024[update], 861 kilometer-sized near-Earth asteroids have been discovered.[13]
